Telecommunications chassis and module

ABSTRACT

A telecommunications system ( 14 ) includes a chassis ( 12 ) defining a front ( 18 ), a rear ( 16 ), and a plurality of first signal connection locations ( 38 ) adjacent the rear ( 16 ). A plurality of removable cassettes ( 10 ) are housed within the chassis ( 12 ), each including a cassette body ( 68 ) defining a fixed portion ( 80 ) that is coupled to one of the first signal connection locations ( 38 ) on the chassis ( 12 ) and a movable portion ( 82 ) that telescopically slides relative to the fixed portion ( 80 ), wherein the movable portion ( 82 ) is configured for movement in a direction from the front ( 18 ) to the rear ( 16 ) of the chassis ( 12 ), each cassette ( 10 ) defining a plurality of second signal connection locations ( 58 ). A cable ( 24 ) between the fixed portion ( 80 ) and the movable portion ( 82 ) extends out from the movable portion ( 82 ) when that portion ( 82 ) is pulled forwardly to an extended position and is retracted into the cassette body ( 68 ) when the movable portion ( 82 ) is pushed rearwardly relative to the fixed portion ( 80 ).

CROSS-REFERENCE TO RELATED APPLICATION

This application is continuation of U.S. patent application Ser. No.16/377,783, filed on Apr. 8, 2019, now U.S. Pat. No. 10,678,011, whichis a continuation of U.S. patent application Ser. No. 15/565,103, filedon Oct. 6, 2017, now U.S. Pat. No. 10,254,497, which is a National StageApplication of PCT/US2016/027342, filed on Apr. 13, 2016, which claimsthe benefit of U.S. Patent Application Ser. No. 62/146,649, filed onApr. 13, 2015, the disclosures of which are incorporated herein byreference in their entireties. To the extent appropriate, a claim ofpriority is made to each of the above disclosed applications.

BACKGROUND

As demand for telecommunications services increases, fiber opticnetworks are being extended in more and more areas. Management of thecables, ease of installation, and ease of accessibility for latermanagement are important concerns. As a result, there is a need forfiber optic devices which address these and other concerns.

SUMMARY

An aspect of the present disclosure relates to fiber optic devices inthe form of fiber optic cassettes and chassis for housing suchcassettes, wherein each cassette includes at least one connector thatprovides a signal entry location and at least one connector thatprovides a signal exit location. A ribbon cable extending from the atleast one connector at the signal entry location toward the at least oneconnector at the signal exit location is managed internally within thebody of the cassette.

In certain embodiments, the cassette includes a fixed portion that isoptically coupled to a backplane of a telecommunications chassis. Thecassette further includes a telescopically movable portion that movestogether with trays/blades that are slidable on the chassis, wherein thetrays/blades support the cassettes. The ribbon cable that includesoptical fibers for relaying fiber optic signals from the fixed portionof the cassette to the movable portion of the cassette extends out ofthe cassette body when the movable portion of the cassette istelescopically pulled out (via the trays/blades). The ribbon cableretracts into the cassette body and is managed internally via spoolswithin the interior of the cassette body when the movable portion ismoved back into the chassis via the trays/blades. The chassis, alongwith the cassettes housed within the chassis, form a part of thetelecommunications system of the present disclosure.

According to another aspect of the present disclosure, atelecommunications system comprises a chassis defining a front, a rear,and a plurality of first signal connection locations provided adjacentthe rear, a plurality of removable cassettes housed within the chassis,each cassette including a cassette body defining a fixed portion that iscoupled to one of the first signal connection locations provided on thechassis and a movable portion that telescopically slides with respect tothe fixed portion, wherein the movable portion of the cassette isconfigured for movement in a direction extending from the front to therear of the chassis, wherein each cassette defines a plurality of secondsignal connection locations, and wherein a cable extending between thefixed portion and the movable portion extends out from the movableportion when the movable portion is pulled forwardly to an extendedposition and the cable is retracted into and managed internally withinthe cassette body when the movable portion is pushed rearwardly withrespect to the fixed portion.

According to another aspect of the present disclosure, a fiber opticcassette comprises a cassette body defining a fixed portion that isconfigured to be fixedly coupled to a telecommunications chassis,wherein the fixed portion defines a fiber optic connector for opticallymating with a fiber optic adapter of the chassis, a movable portion thattelescopically slides with respect to the fixed portion, and a pluralityof fiber optic connection locations defined on the movable portion ofthe cassette body, wherein a cable extending from the fiber opticconnector at the fixed portion toward the movable portion extends outfrom the movable portion when the movable portion is pulled away fromthe fixed portion, and the cable is retracted into and managedinternally within the cassette body when the movable portion and thefixed portion are brought together.

According to another aspect of the present disclosure, a fiber opticcassette comprises a cassette body defining a fixed portion that isconfigured to be fixedly coupled to a telecommunications chassis,wherein the fixed portion defines a fiber optic connector for opticallymating with a fiber optic adapter of the chassis and a movable portionthat telescopically slides with respect to the fixed portion, aplurality of fiber optic adapters defined on the movable portion of thebody, wherein a ribbon cable extending from the fiber optic connector atthe fixed portion toward the movable portion extends out from themovable portion when the movable portion is pulled away from the fixedportion, and the ribbon cable is retracted into and managed internallywithin the cassette body when the movable portion and the fixed portionare brought together, wherein the ribbon cable carries a plurality offibers that extend to the fiber optic adapters defined on the movableportion of the cassette body, wherein the cassette includes a transitionfiber array defined by a polymeric substrate that supports the pluralityof fibers extending from the ribbon cable toward the fiber opticadapters of the movable portion of the cassette body, the fiber opticadapters each configured to mate a standard fiber optic connector to anon-conventional fiber optic connector that is terminated to one of thefibers extending from the ribbon cable and supported by the polymericsubstrate.

According to another aspect of the present disclosure, a method ofmanaging a cable extending from a fiber optic connection locationprovided on a chassis toward a fiber optic cassette that is slidablewithin the chassis comprises moving the fiber optic cassette toward anextended position away from the chassis to expose the cable, and movingthe fiber optic cassette toward a retracted position in the chassis andautomatically spooling the cable within the fiber optic cassette as thefiber optic cassette is moved.

According to yet another aspect of the present disclosure, atelecommunications system comprises a chassis defining a front, a rear,and a plurality of first signal connection locations, a plurality ofcassettes housed within the chassis, at least a portion of each cassetteslidably movable in a direction extending from the front to the rear ofthe chassis, wherein each cassette defines a plurality of second signalconnection locations, and wherein a cable extending between one of thefirst signal connection locations of the chassis and the movable portionof the cassette extends out from the movable portion when the movableportion is pulled forwardly to an extended position, and the cable isretracted into and managed internally within the cassette when themovable portion is pushed rearwardly to a retracted position.

A variety of additional inventive aspects will be set forth in thedescription that follows. The inventive aspects can relate to individualfeatures and combinations of features. It is to be understood that boththe foregoing general description and the following detailed descriptionare exemplary and explanatory only and are not restrictive of the broadinventive concepts upon which the embodiments disclosed herein arebased.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top, front, right side perspective view of a fiber optictelecommunications system having features that are examples of inventiveaspects in accordance with the present disclosure, the system includinga telecommunications chassis that is configured to be mounted on atelecommunications rack, at least one tray or blade slidably mounted onthe telecommunications chassis, and at least one fiber optic cassetteremovably mounted on the blade, wherein the fiber optic cassetteincludes a fixed portion that is coupled to the chassis and atelescopically movable portion that moves with the pull-outtrays/blades;

FIG. 2 illustrates the telecommunications system of FIG. 1 with one ofthe trays in the extended position, wherein the movable portions of thecassettes that are supported by the tray have also been telescopicallyextended;

FIG. 3 illustrates one of the slidable trays/blades of the system ofFIGS. 1-2 in isolation removed from the chassis;

FIG. 4 illustrates the tray/blade of FIG. 3 with the telescopicallymovable portions of the cassettes in an extended position;

FIG. 5 illustrates one of the fiber optic cassettes of the system ofFIGS. 1-2 in isolation removed from one of the trays/blades of thesystem;

FIG. 6 illustrates the cassette of FIG. 5 with the telescopicallymovable portion of the cassette in an extended position;

FIG. 7 illustrates the cassette of FIG. 5 with a cover thereof removedfrom the rest of the cassette body to illustrate the internal featuresthereof, wherein a ribbon cable is in a retracted position, beingmanaged internally within the cassette body;

FIG. 8 illustrates the cassette of FIG. 7 with the telescopicallymovable portion of the cassette in an extended position, with the ribboncable extending out of the cassette body; and

FIG. 9 illustrates a close-up view of a portion of the cassette of FIG.8.

DETAILED DESCRIPTION

The present disclosure is directed generally to fiber optic devices inthe form of fiber optic cassettes 10 and telecommunications chassis 12configured to house such fiber optic cassettes 10, wherein the chassis12 and the cassettes 10 form a part of a telecommunications system 14 ofthe present disclosure. The cassettes 10 may be removable, replaceable,modular units.

As will be described in further detail below, the fiber optic cassettes10 of the present disclosure are designed to relay signals inputadjacent a rear 16 of the chassis 12 toward connection locationsadjacent a front 18 of the chassis 12 for further distribution.

Each cassette 10 houses and directs multiple fibers which terminate at arear connector 92, such as an MPO style connector, to a plurality ofadapters 58 positioned at a generally front portion of the cassette 10.The fiber optic cassettes 10 of the present disclosure are designed tointernally manage the cabling 24 carrying the fibers as trays/blades 26supporting the cassettes 10 move between an extended position and aretracted position.

According to certain embodiments, the fiber optic cassettes 10 of thepresent disclosure provide a transition housing or support betweenmulti-fibered connectors, such as MPO style connectors having MTferrules, and single or dual fiber connectors, such as LC or SC typeconnectors, wherein that transition housing or support includes featuresfor internally managing cabling 24 as the cassettes 10 move between theextended and retracted positions.

Referring now to FIGS. 1-2, a fiber optic telecommunications system 14having features that are examples of inventive aspects in accordancewith the present disclosure is illustrated. The system 14 includes atelecommunications chassis or panel 12 configured to be mounted on atelecommunications rack. In the depicted embodiment, the chassis 12 issized to be mountable on a standard 19-inch telecommunications rack.

According to the depicted embodiment, the chassis 12 is defined by aright wall 28 and a left wall 30. The right and left walls 28, 30 definemounting flanges 32 adjacent a front 18 of the chassis 12 for mountingthe chassis 12 to a telecommunications rack.

Adjacent a rear 16 of the chassis 12, a back wall 34 extends between theright and left walls 28, 30 of the chassis 12. The back wall 34 definesa fiber optic backplane 36 consisting of a plurality of fiber opticadapters 38 arranged in parallel rows and columns. In the depictedembodiment, the backplane 36 defines MPO style fiber optic adapters 38that are configured to receive and couple MPO style fiber opticconnectors. Each of the cassettes 10 supported by the trays 26 of thechassis 12 are configured to be optically coupled to the backplane 36for receiving input signals.

Still referring to FIGS. 1-2, in the depicted embodiment of the chassis12, a pair of cable management structures 40 in the form of cable ringsare provided at the front 18 of the chassis 12 at each of the right andleft walls 28, 30. The cable rings 40 are configured to manage cablesleading to or away from the optical cassettes 10 that are housed withinthe chassis 12. Further details relating to cable management structuressimilar to cable rings 40 are described and illustrated in InternationalPublication No. WO 2015/040211, the entire disclosure of which isincorporated herein by reference.

A front door 42 of the chassis 12 extends between the right and leftwalls 28, 30 and is pivotally opened to provide access to the connectionlocations defined by the optical cassettes 10 within the chassis 12.Further details relating to the door 42 and a hinge arrangement thatallows the door 42 to be movable between a fully closed position and afully open position that is at 180 degrees from the fully closedposition are described and illustrated in International Publication No.WO 2016/012295, the entire disclosure of which is incorporated herein byreference. The hinge mechanism 44 of the door 42 allows the door to befully opened, enabling extension or removal of the pull-out trays/blades26 housed within the chassis 12.

Still referring to FIGS. 1-2, in the depicted embodiment, the chassis 12is configured to have a height of two standard rack units (2RU). Otherheights are possible. Within the 2RU height, the chassis 12 isconfigured to house eight blades or trays 26 that are mounted in avertically stacked arrangement within the chassis 12. One of the blades26 (populated with the cassettes 10 of the present disclosure) is shownin isolation in FIGS. 3-4.

As shown, each blade 26 defines a generally planar configuration withslide portions 46 defined at each of the right and left sides 48, 50 ofthe blade 26. And, as shown in FIGS. 1-2, at each of the right and leftwalls 28, 30, the chassis 12 defines mounting slots 52 for receiving theslide portions 46 of the blades 26. The slide portions 46 of the blades26 and the mounting slots 52 of the chassis walls 28, 30 are configuredto cooperate such that positive stops are provided for predeterminedpositions of the blades 26 with respect to the chassis 12. For example,a positive stop may be provided when the blade 26 is at a neutral(retracted) position within the chassis 12. Once the blade 26 is pulledout by a user toward an extended position, another positive stop may beprovided at the fully extended position to keep the blade 26 coupled tothe chassis 12. If the blade 26 needs to be fully removed from thechassis 12, the slide portions 46 of the blade 26 may be flexed inwardlyto remove tabs defined by the slide portions 46 from notches definedwithin the mounting slots 52 of the chassis 12, and the blade 26 pulledout.

Further details relating to the slide mechanism provided between thechassis 12 and the individual trays/blades 26 and the operation thereofis described and illustrated in International Publication No. WO2015/040211, the entire disclosure of which has been incorporated hereinby reference.

As noted above, in the depicted telecommunications system 14, theblades/trays 26 of the chassis 12 are used for supportingtelecommunications devices in the form of fiber optic cassettes 10 thatare for relaying fiber optic signals. Cable management devices 54 may bepositioned between each of the cassettes 10 for managing cablesextending from the front sides 60 of the cassettes 10. In the depictedembodiment, each tray/blade 26 is sized to hold five fiber opticcassettes 10 along a row within the 19-inch standard rack spacing. Oneexample of a cassette 10 that is configured for mounting on the chassis12 is shown in isolation in FIGS. 5-9, further details of which will bedescribed below.

According to one example embodiment, the depicted cassette 10 isconfigured to provide twelve connection locations 58 defined by standardLC format adapters at the front 60 of the cassette 10, as will bediscussed in further detail below. The LC adapters 58 may be formed aspart of an adapter block 62. With five cassettes 10 located on eachblade 26, and with eight blades 26 located on each chassis 12, thechassis 12 can accommodate a density of 480 standard LC formatconnections within a 2RU rack spacing. A similar 1RU chassis 12 can,thus, accommodate 240 standard LC format connections within that 1RUspacing. Although, the density noted provides the maximum capacity forthe system 14, other connection location numbers may be utilized on thechassis 12. For example, in other embodiments, the chassis 12 mayutilize 180 standard LC format connections within a 1RU space. In yetother embodiments, the chassis may utilize 210 standard LC formatconnections within a 1RU space if the chassis is large enough to have a2RU or greater capacity.

Now referring specifically to FIGS. 5 and 6, the blades 26 and thecassettes 10 are configured such that portions (e.g., at the bottom) ofthe cassettes 10 are configured to receive portions of the blades 26 todecrease the overall thickness of the mounted unit. Each cassette 10defines a notched area 64 that extends a majority of the length of thecassette 10, essentially from where the adapter block 62 is positionedto the rear 66 of the cassette 10. As such, according to one exampleembodiment, when a cassette 10 is mounted on a blade 26, the blade 26lies flush with the cassette body 68, and the thickness of the blade 26is accommodated by the notched area 64. As such, when a cassette 10 ismounted on the blade 26, the cassette 10 can abut and lie against theblade 26 without substantially adding to the overall thickness of theunit. According to one example embodiment, the entire thickness of theblade 26 is accommodated by the notched area 64. According to anotherexample embodiment, at least a portion of the thickness of the blade 26is accommodated by the notched area 64. According to yet another exampleembodiment, at least a portion of the notched area 64 is used inaccommodating the thickness of the blade 26 such that the blade bodydoes not add to the maximum overall height of the cassette 10.

As noted above, this configuration allows four cassette-loaded blades 26to be mounted in a vertical stack in a 1RU rack space and eightcassette-loaded blades 26 to be mounted in a vertical stack in a 2RUrack space.

The cable managers 54, discussed above, located between each fiber opticcassette 10, help preserve the high density provided by the system 14.As depicted, each cable manager 54 defines wider portions 70 at thefront ends 72 thereof that transition to a rear section 74 having athinner profile. The wider portions 70 define split-ring configurationsfor receiving and retaining cables extending to and from the cassettes10. The thinner profile sections 74 are positioned between the cassettes10 when the cable managers 54 are mounted to the blades 26 to preservethe overall density within a 19-inch rack.

The thin portions 74 of the cable managers 54 allow five cassettes 10,each holding up to twelve connections, to be mounted on blades 26 alonga horizontal stack within the width defined by a standard 19-inchtelecommunications rack. And, with four cassette-loaded blades 26mounted in a vertical stack in a 1RU rack space, the system 14 of thepresent disclosure achieves significant connectivity densities.

As previously noted, according to one example embodiment, a maximumcapacity of 480 connections each using a standard LC connector footprintare achieved in a standard 19-inch telecommunications rack within a 2RUrack space. According to another example embodiment, a maximum capacityof 240 connections each using a standard LC connector footprint areachieved in a standard 19-inch telecommunications rack within a 1RU rackspace, as noted above.

The removability of the cassettes 10 provides significant flexibility inconfiguring the connectivity of system 14 as desired. For example, theblades 26 may be populated and the cassettes 10 arranged differentlydepending upon the densities needed and the different types and sizes ofcabling used (e.g., 12 fiber 10-gig cabling, 24 fiber 40-gig cabling, or48 fiber 100-gig cabling).

The removability of the cassettes 10 and the blades 26 of the systems 14of the present disclosure allows different arrangements to be provideddepending upon the connectivity need. Cassettes 10 can be added forincreasing connectivity, removed for decreasing connectivity, orreplaced if needing repair. The connection locations can be varied bothin number and type. For example, the types of optical equipment (e.g.,the types of cassettes 10) can be varied within each blade 26 or withinthe different levels within a chassis 12. Certain mounting locations ofthe blades 26 can be left unpopulated and used for other purposes suchas labeling, etc.

Now referring to FIGS. 5-9 in general, the parts that make up the body68 of one example cassette 10 having inventive aspects in accordancewith the present disclosure are shown. The cassette body 68 is definedby a base 76 and a cover 78. The cassette body 68 defines a rear end 66and a front end 60. As shown, an adapter block 62 is positioned at thefront end 60 of the body 68. The adapter block 62 may be formed as anintegral part of the base 76, or may be provided as a removablestructure that is captured thereagainst by the cover 78. Similar fiberoptic adapter blocks 62, including those that might have staggeredadapter configurations, are described and illustrated in further detailin U.S. Pat. No. 9,075,203, which patent is incorporated herein byreference in its entirety.

The base 76 of the cassette body 68, as will be described in furtherdetail below, defines a fixed portion 80 and a movable portion 82 thatis configured to telescopically slide with respect to the fixed portion80. The two portions 80, 82 of the base 76 facilitate management of thecable 24 that is carrying the fibers supported by the cassette 10. Apair of slide rods 84 are provided for guiding and supporting theslidably movable portion 82 with respect to the fixed portion 80.

As shown in FIGS. 5-9, the slide rods 84 extend through both the fixedportion 80 and the movable portion 82 of the base 76 of the cassettebody 68. The slide rods 84 are configured such that they may also beslidable with respect to the base 76 of the cassette body 68. Each sliderod 84 defines a stop flange 86 at a rear end 88 thereof that caninteract with the fixed portion 80 of the base 76 to prevent removal ofthe slide rod 84 from the fixed portion 80. When the movable portion 82of the base 76 starts to telescopically slide with respect to the fixedportion 80, the slide rod 84 may also slidably move until the stopflange 86 abuts the fixed portion 80 of the base 76, at which point, themovable portion 82 starts sliding with respect to the rod 84.

According to certain embodiments, portions of the cassette body 68 maybe formed from polymeric materials. The slide rods 84 may be formed froma metallic material for further rigidity.

The fixed portion 80, as will be described in further detail below,defines a fiber optic adapter 90 (e.g., in the form of an MPO styleadapter) at the rear end 66 of the cassette body 68. A fiber opticconnector 92 (in the form of an MPO connector) extends rearwardly fromthe MPO style adapter 90. The fiber optic connector 92 is configured forcoupling to the adapters 38 provided at the backplane 36 of the chassis12 for inputting signals into the cassettes 10.

The movable portions 82 of the cassette bodies 68 are coupled to andsupported by the blades 26 of the chassis 12 and are configured to movewith those blades 26. As such, when the fixed portion 80 of eachcassette 10 is physically and optically coupled to the backplane 36defined by the chassis 12, the movable portion 82 moves with thetrays/blades 26 as the blades/trays 26 are pulled out from the chassis12.

Still referring to FIGS. 5-9, the fiber optic connector 92 extendingrearward from the cassette 10 provides a signal entry location for thecassette 10. And, the individual connector ports defined by the adapters58 of the adapter block 62 at the front 60 of the cassette 10 providesignal exit locations.

A ribbon cable 24 terminated to and extending from the connector 92 atthe signal entry location includes a plurality of fibers that carrysignals being relayed toward the adapters 58 at the front 60 of thecassette 10. The cassette 10 is configured such that the ribbon cable 24moves from a position where it extends out of the cassette body 68 whenthe movable portion 82 of the base 76 has been telescopically pulled out(shown in FIGS. 8-9) to a retracted and managed position when themovable portion 82 has been retracted back to the neutral position(shown in FIG. 7). The ribbon cable 24 enters the movable portion 82 ofthe base 76 through an opening 94 adjacent the rear end 99 of themovable portion 82. Once the ribbon cable 24 enters the movable portion82, it is guided toward (with bend radius protection) and managedinternally via spools 96, 98 within the interior 100 defined by the base76. When the movable portion 82 is retracted via the trays/blades 26,the ribbon cable 24 can coil and be managed within the interior 100defined by the movable portion 82 of the base 76.

As shown in FIGS. 7-9, the base 76 defines a large spool 96 surroundinga small spool 98 for management of the ribbon cable 24. The purpose ofthe two spools 96, 98 will be described in further detail below.

Still referring to FIGS. 5-9, according to certain example embodiments,as shown in the depicted cassette 10, within an interior 100 defined bythe cassette body 68, the cassette 10 may utilize a transitional fiberarray 102. According to certain embodiments, such a transitional fiberarray 102 may or may not include a flexible substrate forming a flexibleoptical circuit for the transition of the fibers. In the depictedembodiment, the fiber array 102 is configured to branch out the fibersof the ribbon cable 24 and relay the fibers toward the adapters 58positioned at the front 60 of the cassette 10.

In FIGS. 7-9, the fiber array 102 is shown as being supported by a rigidpolymeric insert 104 that has been placed within the base 76 of thecassette body 68. Further details relating to the polymeric insert 104and the method for manufacturing thereof are described and illustratedin U.S. Patent Publication No. 2016/0041357, the entire disclosure ofwhich is incorporated herein by reference.

A rigid insert 104, as the one shown in FIGS. 7-9, may define individualchannels at a front end of the insert 104 where fibers can transition toa fiber consolidation point 106 at a rear end 108 of the insert 104. Thechannels may define curved rear portions. The curvature of the channelsmay be designed to protect the minimum bend radius requirements of thefibers as the fibers extend rearwardly from the front end 110 to therear end 108 of the insert 104. At the fiber consolidation point 106 atthe rear end 108 of the insert 104, the fiber optic array 102 may definea clamp for clamping the consolidated fibers. The fiber clamp may beconfigured to keep the consolidated fibers in a given arrangement asthey transition between the ribbon cable 24 and the branched fiber array102.

As noted above, the polymeric insert 104, rather than being provided asa rigid structure, may also be replaced with a flexible substrate toprovide a flexible optical circuit. Flexible optical circuits arepassive optical components that comprise one or more (typically,multiple) optical fibers embedded on a flexible substrate, such as aMylar™ material or other flexible polymer substrate. Commonly, althoughnot necessarily, one end face of each fiber is disposed adjacent onelongitudinal end of the flexible optical circuit substrate, and theother end face of each fiber is disposed adjacent the oppositelongitudinal end of the flexible optical circuit substrate. The fibersextend past the longitudinal ends of the flexible optical circuit(commonly referred to as pigtails) so that they can be terminated tooptical connectors, which can be coupled to fiber optic cables or otherfiber optic components through mating optical connectors.

Flexible optical circuits essentially comprise one or more fiberssandwiched between two flexible sheets of material, such as Mylar™material or another polymer. An epoxy may be included between the twosheets in order to adhere them together. Alternately, depending on thesheet material and other factors, the two sheets may be heated abovetheir melting point to heat-weld them together with the fibers embeddedbetween the two sheets.

In the depicted embodiment of the cassette 10, even though the fiberarray 102 is shown to be supported by a rigid polymeric insert 104, inother embodiments, the cassette 10 may utilize a flexible circuitdefined by a flexible substrate. Further details relating to cassettesutilizing flexible optical circuits are described and illustrated in WO2014/052441 and WO 2014/052446, the entire disclosures of which areincorporated herein by reference.

The use of flexible optical circuits within the fiber optic cassettes 10of the present disclosure may provide certain advantages. For example,the substrate of a flexible optical circuit may be mechanicallyflexible, being able to accommodate tolerance variations in differentcassettes 10, such as between connector ferrules and the housings thatform the cassettes 10. The flexibility of the optical circuits alsoallow for axial movement in the fibers to account for ferrule interfacevariation. Also, providing a supportive substrate 104, either rigid orflexible, within which the fibers are positionally fixed, allows adesigner to optimize the fiber bend radius limits and requirements inconfiguring the cassettes 10, thus, achieving reduced dimensions of thecassettes 10. The bend radius of the fibers can thus be controlled to aminimum diameter. By utilizing optical fibers such as bend insensitivefibers (e.g., 8 mm bend radius) in combination with a rigid insert 104or a flexible substrate that fixes the fibers in a given orientation,allowing for controlled bending, small form cassettes 10 may be producedin a predictable and automated manner. Manual handling and positioningof the fibers within the cassettes 10 may be reduced and eliminatedthrough the use of such fiber arrays 102.

According to one example embodiment, in the fiber optic cassette 10 ofthe present disclosure, the fiber array 102 is provided between theribbon cable 24 and the adapter block 62 located at the front 60 of thecassette 10. The array 102 separates and relays the individual fibers ofthe ribbon cable 24 toward the adapter block 62. As discussed in WO2014/052441, WO 2014/052446, and U.S. Patent Publication No.2016/0041357, the entire disclosures of which have been incorporatedherein by reference, the array 102 can be used to transition opticalfibers between a standard multi-fiber ribbon cable 24 to a plurality ofnon-conventional connectors 112 at the opposite front end 60 of thecassette body 68. If the array 102 uses a flexible substrate defining aflexible circuit, portions of that substrate supporting the fibers maybe physically inserted into the non-conventional connectors 112.

It should be noted that the term “non-conventional connector” may referto a fiber optic connector that is not of a conventional type such as anLC or SC connector and one that has generally not become a recognizablestandard footprint for fiber optic connectivity in the industry.

As described and shown in WO 2014/052441, WO 2014/052446, and U.S.Patent Publication No. 2016/0041357, the entire disclosures of whichhave been incorporated by reference, the non-conventional connectors 112that are positioned adjacent the front 60 of the cassette 10 may eachdefines a hub mounted over a ferrule. A split sleeve may also beprovided for ferrule alignment between the hub and ferrule of eachnon-conventional connector 112 and a ferrule of another mating connectorthat enters the cassette 10 from the front 60. Each ferrule may beconfigured to terminate one of the fibers extending out from the insert104. The fiber pigtails extending out from a front end 110 of the insert104 may be individually terminated to the ferrules to be positioned atthe front 60 of the cassette 10.

The cassette 10 may define pockets 114 at the rear end 116 of theadapter block 62 that match the exterior shape of the ferrule hubs(e.g., having square footprints), wherein the pockets 114 may beconfigured to fully surround the ferrule hubs. Via the adapter block 62,the cassette 10 is ready to receive fiber optic connections. Matingconventional connectors entering the cassette 10 from the front 60 ofthe cassette 10 may be connected through fiber optic adapters 58 thatare defined by the adapter block 62.

The elimination of conventional mating connectors inside the cassette 10may significantly reduce the overall cost by eliminating the skilledlabor normally associated with terminating an optical fiber to aconnector, including polishing the end face of the fiber and epoxyingthe fiber into the connector. It further allows the fiber opticinterconnect device such as the optical cassette 10 to be made verythin.

As noted, further details relating to fiber optic cassettes includingsuch non-conventional connectors 112 are described and illustrated inthe above-incorporated WO 2014/052441, WO 2014/052446, and U.S. PatentPublication No. 2016/0041357.

Referring to FIGS. 5-9, for the cassette 10 shown therein, a signalentry location may be provided by an MPO style adapter 90 and an MPOstyle connector 92 that is within the adapter 90 at the fixed portion 80of the base 76 of the cassette body 68. The ribbon cable 24 terminatedto the MPO connector 92 carries the fibers that are relayed to themovable portion 82 of the base 76 of the cassette body 68. From theribbon cable 24, the fibers are transitioned via a fiber optic array 102that is supported by a polymeric insert 104 that is placed within thecassette body 68. The pigtails extending forward from the polymericinsert 104 may be used to form the non-conventional connectors 112 asnoted above. The adapter block 62 at the front end 60 of the cassettebody 68 may be configured to mate the non-conventional connectors 112positioned at a rear end 116 of the block 62 to conventional typeconnectors (e.g., LC format) coming in from the front 60 of the cassette10.

Regarding the management of the ribbon cable 24 within the cassette body68 and the two spools 96, 98, the large spool 96 is used when the fiberscarried by the ribbon cable 24 are initially terminated within thecassette 10, the ribbon cable 24 extending from the MPO connector 92provided within the MPO adapter 90 at the fixed portion 80 to thepolymeric insert 104 within the movable portion 82.

The small spool 98 is used if, for any reason, the ribbon cable 24 hasto be re-terminated. When re-terminating a ribbon cable 24 such as theone used with the cassettes 10 of the present disclosure, the cable 24is cut and the technician can normally lose 20-30 mm of the cablelength. The cassette 10 of the present disclosure is designed such thatthe small spool 98 defines a fiber path 118 that surrounds the spool 98that is about 30-40 mm shorter than that defined by the large spool 96.Thus, using the small loop or path 118, after a re-termination process,ensures that the ribbon cable 24 will still be able to extend to itsfully extended length when the telescopically movable portion 82 ispulled out. The difference in length between the path 118 surroundingthe large loop 96 (which is initially used when assembling the cassette10) and the path 118 surrounding the small loop 98 is large enough tomake up the length that is lost in re-terminating the ribbon cable 24.Thus, the cooperation and the positioning of the two spools 96, 98provides a guide to a technician that may be re-terminating the ribboncable 24. The two spools 96, 98 retain the proper functioning of thecassette 10 by preventing or limiting any stress that might be put onthe fibers of the ribbon cable 24 via the telescoping movement of thecassette 10 if such a guide was not used. It should be noted that inFIG. 7, the ribbon cable 24 is illustrated in an initially terminatedconfiguration where the large spool 96 is used for managing the cable24. In FIG. 8, the cassette 10 is shown when a ribbon cable 24 has beenre-terminated, where the cable 24 is now managed by the small spool 98.FIG. 9 is a close-up view of a portion of the cassette 10 of FIG. 8,wherein the difference between the fiber paths 118 between the twospools 96, 98 is illustrated schematically.

As shown in FIGS. 5-9, the fixed portion 80 of the base 76 defines anotch 120 for accommodating the spools 96, 98 formed within the movableportion 82 of the base 76. The movable portion 82 of the base 76 alsodefines a notch 122 for accommodating a portion of the fiber opticadapter 90 provided on the fixed portion 80 of the base 76. The notches120, 122 provide a flush fit when the movable and the fixed portions 82,80 of the base 76 of the cassette body 68 are brought together.

Although in the foregoing description, terms such as “top,” “bottom,”“front,” “back,” “right,” “left,” “upper,” and “lower” were used forease of description and illustration, no restriction is intended by suchuse of the terms. The telecommunications devices described herein can beused in any orientation, depending upon the desired application.

Having described the preferred aspects and embodiments of the presentdisclosure, modifications and equivalents of the disclosed concepts mayreadily occur to one skilled in the art. However, it is intended thatsuch modifications and equivalents be included within the scope of theclaims which are appended hereto.

LIST OF REFERENCE NUMERALS AND CORRESPONDING FEATURES

-   10—Fiber optic cassette-   12—Telecommunications chassis-   14—Telecommunications system-   16—Rear of chassis-   18—Front of chassis-   24—Ribbon cable-   26—Tray/blade-   28—Right wall of chassis-   30—Left wall of chassis-   32—Mounting flange-   34—Back wall of chassis-   36—Backplane-   38—Connection location/fiber optic adapter-   40—Cable management structures/cable rings-   42—Door-   44—Hinge mechanism-   46—Slide portion of blade-   48—Right side of blade-   50—Left side of blade-   52—Mounting slot-   54—Cable management device-   58—Connection location/fiber optic adapter-   60—Front end of cassette-   62—Adapter block-   64—Notched area-   66—Rear end of cassette-   68—Cassette body-   70—Wider portion of cable manager-   72—Front end of cable manager-   74—Thin portion of cable manager-   76—Base of cassette body-   78—Cover of cassette body-   80—Fixed portion of base-   82—Movable portion of base-   84—Slide rod-   86—Stop flange-   88—Rear end of slide rod-   90—Fiber optic adapter-   92—Fiber optic connector-   94—Opening-   96—Large spool-   98—Small spool-   99—Rear end of movable portion of base-   100—Interior-   102—Fiber optic array-   104—Polymeric insert-   106—Fiber consolidation point-   108—Rear end of insert-   110—Front end of insert-   112—Non-conventional connector-   114—Pocket-   116—Rear end of adapter block-   118—Fiber path-   120—Notch-   122—Notch

What is claimed is:
 1. A telecommunications system comprising: a chassisdefining a front, a rear, and a plurality of first signal connectionlocations; a plurality of cassettes mounted to the chassis, eachcassette including a cassette body defining a fixed portion that iscoupled to one of the first signal connection locations provided on thechassis and a movable portion that moves with respect to the fixedportion; wherein each cassette defines at least one second signalconnection location; wherein a cable extending between the fixed portionand the movable portion extends out from the movable portion so as to beexposed to an exterior of the cassette body when the movable portion ismoved away from the fixed portion, and the cable is managed by thecassette body when the movable portion is moved back toward the fixedportion.
 2. The telecommunications system of claim 1, wherein the firstand second signal connection locations are configured for relaying fiberoptic signals.
 3. The telecommunications system of claim 2, wherein thefirst and second signal connection locations are defined by fiber opticadapters.
 4. The telecommunications system of claim 3, wherein eachcassette defines a plurality of the second signal connection locations,wherein the plurality of first signal connection locations are providedby MPO style fiber optic adapters and the plurality of second signalconnection locations are provided by LC type fiber optic adapters. 5.The telecommunications system of claim 1, wherein the plurality ofcassettes are supported by blades that are slidably mounted to thechassis, the blades slidable in a direction extending from the front tothe rear of the chassis.
 6. The telecommunications system of claim 5,wherein the body of each cassette defines a notched area for receiving aportion of the blade on which the cassette is mounted such that theblade does not increase the overall maximum height defined by thecassette body.
 7. The telecommunications system of claim 3, wherein thefixed portion of the cassette body includes a fiber optic connector thatextends from the cassette body that is optically coupled to one of thefiber optic adapters defining the first signal connection locations. 8.The telecommunications system of claim 7, wherein each cassette definesa plurality of the second signal connection locations, wherein the cableis a fiber optic ribbon cable that is terminated to the fiber opticconnector and that carries a plurality of fibers leading to theplurality of second signal connection locations of the cassette.
 9. Thetelecommunications system of claim 8, wherein the cassette includes atransition fiber array defined by a polymeric substrate that supportsthe plurality of fibers extending from the ribbon cable toward theplurality of second signal connection locations of the cassette.
 10. Thetelecommunications system of claim 9, wherein the polymeric substrate isformed from a flexible material.
 11. The telecommunications system ofclaim 9, wherein the fiber optic adapters defining the plurality ofsecond signal connection locations are each configured to mate anexterior fiber optic connector to a fiber optic connector that isterminated to one of the fibers extending from the ribbon cable andsupported by the polymeric substrate.
 12. The telecommunications systemof claim 1, wherein the movable portion of the cassette body defines afirst cable management spool for managing the cable and a back-up secondcable management spool that provides for a shorter-length cable pathmeasured from one of the respective first signal connection locations tothe at least one second signal connection location within a givencassette as compared to a cable path provided by the first cablemanagement spool, the back-up second cable management spool configuredfor use when re-terminating the cable.
 13. A fiber optic cassettecomprising: a cassette body defining a fixed portion that is configuredto be fixedly coupled to a telecommunications chassis, wherein the fixedportion defines a fiber optic connector for optically mating with afiber optic adapter of the chassis and a movable portion that moves withrespect to the fixed portion; and at least one fiber optic connectionlocation defined on the movable portion of the cassette body, wherein acable extending from the fiber optic connector at the fixed portiontoward the movable portion extends out from the movable portion so as tobe exposed to an exterior of the cassette body when the movable portionis moved away from the fixed portion, and the cable is managed by thecassette body when the movable portion and the fixed portion are broughttogether.
 14. The fiber optic cassette of claim 13, wherein the fiberoptic cassette defines a plurality of the fiber optic connectionlocations on the movable portion of the cassette body, wherein the cableis a ribbon cable terminated to the fiber optic connector and carries aplurality of fibers that extend to the plurality of fiber opticconnection locations defined on the movable portion of the cassettebody.
 15. The fiber optic cassette of claim 14, wherein the cassetteincludes a transition fiber array defined by a polymeric substrate thatsupports the plurality of fibers extending from the ribbon cable towardthe plurality of fiber optic connection locations of the movable portionof the cassette body.
 16. The fiber optic cassette of claim 15, whereinthe polymeric substrate is formed from a flexible material.
 17. Thefiber optic cassette of claim 15, wherein the plurality of fiber opticconnection locations of the cassette are defined by fiber optic adaptersthat are each configured to mate an exterior fiber optic connector to afiber optic connector that is terminated to one of the fibers extendingfrom the ribbon cable and supported by the polymeric substrate.
 18. Thefiber optic cassette of claim 13, wherein the movable portion of thecassette body defines a first cable management spool for managing thecable and a back-up second cable management spool that provides for ashorter-length cable path measured from the fiber optic connector to theat least one fiber optic connection location defined on the movableportion of the cassette body as compared to a cable path provided by thefirst cable management spool, the back-up second cable management spoolconfigured for use when re-terminating the cable.